Question

Inversion of DNA sequences within chromosomes is a common process in evolution. The following gene arrangements in a particular chromosome are found in four different species: First sequence: STUVWX Second sequence: UVXTSW Third sequence: UVWSTX Fourth sequence: SWVUTX Assuming that the arrangement in the first sequence is the ancestor/reference arrangement, in what evolutionary order did the four species arise, such that the fewest number of inversions occur between each species (place the first sequence as the earliest species in your ordering)2341

Answer 1

Answer:

The correct answer is - 1, 4, 3, 2.

Explanation:

It is given that the first sequence represents the earliest or ancestor species therefore, the first sequence would be - STUVWX

After the inversion, the highlighted sequence of the first sequence STUVWX gives rise to the second sequence as:

STUVWX

SWVUTX

Thus the second sequence after Ist inversion would be SWVUTX

2nd inversion, Third sequence:

SWVUTX

UVWSTX

Thus the third sequence after 2nd inversion is UVWSTX

3rd inversion, fourth sequence:

UVWSTX

UVXTSW

Thus, the fourth sequence after 3rd inversion is UVXTSW